Commit Graph

13 Commits

Author SHA1 Message Date
Cyrill Gorcunov
047a3772fe perf, x86: P4 PMU - Fix unflagged overflows handling
Don found that P4 PMU reads CCCR register instead of counter
itself (in attempt to catch unflagged event) this makes P4
NMI handler to consume all NMIs it observes. So the other
NMI users such as kgdb simply have no chance to get NMI
on their hands.

Side note: at moment there is no way to run nmi-watchdog
together with perf tool. This is because both 'perf top' and
nmi-watchdog use same event. So while nmi-watchdog reserves
one event/counter for own needs there is no room for perf tool
left (there is a way to disable nmi-watchdog on boot of course).

Ming has tested this patch with the following results

 | 1. watchdog disabled
 |
 | kgdb tests on boot OK
 | perf works OK
 |
 | 2. watchdog enabled, without patch perf-x86-p4-nmi-4
 |
 | kgdb tests on boot hang
 |
 | 3. watchdog enabled, without patch perf-x86-p4-nmi-4 and do not run kgdb
 | tests on boot
 |
 | "perf top" partialy works
 |   cpu-cycles            no
 |   instructions          yes
 |   cache-references      no
 |   cache-misses          no
 |   branch-instructions   no
 |   branch-misses         yes
 |   bus-cycles            no
 |
 | 4. watchdog enabled, with patch perf-x86-p4-nmi-4 applied
 |
 | kgdb tests on boot OK
 | perf does not work, NMI "Dazed and confused" messages show up
 |

Which means we still have problems with p4 box due to 'unknown'
nmi happens but at least it should fix kgdb test cases.

Reported-by: Jason Wessel <jason.wessel@windriver.com>
Reported-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Acked-by: Don Zickus <dzickus@redhat.com>
Acked-by: Lin Ming <ming.m.lin@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4D275E7E.3040903@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-09 10:40:52 +01:00
Cyrill Gorcunov
af86da5318 perf, x86: P4 PMU - describe config format
Add description of .config in a sake of RAW events.
At least this should bring some light to those who
will be reading this code.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Reviewed-by: Stephane Eranian <eranian@google.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-26 15:14:57 +01:00
Cyrill Gorcunov
c9cf4a019c perf, x86, Pentium4: Add RAW events verification
Implements verification of

- Bits of ESCR EventMask field (meaningful bits in field are hardware
  predefined and others bits should be set to zero)

- INSTR_COMPLETED event (it is available on predefined cpu model only)

- Thread shared events (they should be guarded by "perf_event_paranoid"
  sysctl due to security reason). The side effect of this action is
  that PERF_COUNT_HW_BUS_CYCLES become a "paranoid" general event.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Tested-by: Lin Ming <ming.m.lin@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <20100825182334.GB14874@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-09-01 08:26:56 +02:00
Cyrill Gorcunov
39ef13a4ac perf, x86: P4 PMU -- redesign cache events
To support cache events we have reserved the low 6 bits in
hw_perf_event::config (which is a part of CCCR register
configuration actually).

These bits represent Replay Event mertic enumerated in
enum P4_PEBS_METRIC. The caller should not care about
which exact bits should be set and how -- the caller
just chooses one P4_PEBS_METRIC entity and puts it into
the config. The kernel will track it and set appropriate
additional MSR registers (metrics) when needed.

The reason for this redesign was the PEBS enable bit, which
should not be set until DS (and PEBS sampling) support will
be implemented properly.

TODO
====

 - PEBS sampling (note it's tricky and works with _one_ counter only
   so for HT machines it will be not that easy to handle both threads)

 - tracking of PEBS registers state, a user might need to turn
   PEBS off completely (ie no PEBS enable, no UOP_tag) but some
   other event may need it, such events clashes and should not
   run simultaneously, at moment we just don't support such events

 - eventually export user space bits in separate header which will
   allow user apps to configure raw events more conveniently.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1278295769.9540.15.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-07-05 08:34:36 +02:00
Cyrill Gorcunov
ce7f15452c perf, x86: P4 PMU -- add missing bit in CCCR mask
Should be there for the sake of RAW events.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Lin Ming <ming.m.lin@intel.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100518212439.354345151@openvz.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-19 09:41:06 +02:00
Cyrill Gorcunov
d814f30105 x86, perf: Add raw events support for the P4 PMU
The adding of raw event support lead to complete code
refactoring. I hope is became more readable then it was.

The list of changes:

1)  The 64bit config field is enough to hold all information we need
    to track event details. To achieve it we used *own* enum for
    events selection in ESCR register and map this key into proper
    value at moment of event enabling.

    For the same reason we use 12LSB bits in CCCR register -- to track
    which exactly cache trace event was requested. And we cear this bits
    at real 'write' moment.

2)  There is no per-cpu area reserved for P4 PMU anymore. We
    don't need it. All is held by config.

3)  Now we may use any available counter, ie we try to grab any
    possible counter.

v2:
  - Lin Ming reported the lack of ESCR selector in CCCR for cache events

v3:
  - Don't loose cache event codes at config unpacking procedure, we may
    need it one day so no obscure hack behind our back, better to clear
    reserved bits explicitly when needed (thanks Ming for pointing out)

  - Lin Ming fixed misplaced opcodes in cache events

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Tested-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1269403766.3409.6.camel@minggr.sh.intel.com>
[ v4: did a few whitespace fixlets ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-26 08:45:49 +01:00
Lin Ming
40b7e05e17 perf, x86: Fix key indexing in Pentium-4 PMU
Index 0-6 in p4_templates are reserved for common hardware
events. So p4_templates is arranged as below:

    0  -    6:  common hardware events
    7  -    N:  cache events
  N+1  -  ...:  other raw events

Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Acked-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1268983738.13901.142.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-19 09:23:17 +01:00
Cyrill Gorcunov
9c8c6bad31 x86, perf: Fix few cosmetic dabs for P4 pmu (comments and constantify)
- A few ESCR have escaped fixing at previous attempt.
- p4_escr_map is read only, make it const.

Nothing serious.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Lin Ming <ming.m.lin@intel.com>
LKML-Reference: <20100318211256.GH5062@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-18 22:17:46 +01:00
Lin Ming
cb7d6b5053 perf, x86: Add cache events for the Pentium-4 PMU
Move the HT bit setting code from p4_pmu_event_map to
p4_hw_config. So the cache events can get HT bit set correctly.

Tested on my P4 desktop, below 6 cache events work:

 L1-dcache-load-misses
 LLC-load-misses
 dTLB-load-misses
 dTLB-store-misses
 iTLB-loads
 iTLB-load-misses

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1268908392.13901.128.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-18 17:04:02 +01:00
Lin Ming
f34edbc1cd perf, x86: Add a key to simplify template lookup in Pentium-4 PMU
Currently, we use opcode(Event and Event-Selector) + emask to
look up template in p4_templates.

But cache events (L1-dcache-load-misses, LLC-load-misses, etc)
use the same event(P4_REPLAY_EVENT) to do the counting, ie, they
have the same opcode and emask. So we can not use current lookup
mechanism to find the template for cache events.

This patch introduces a "key", which is the index into
p4_templates. The low 12 bits of CCCR are reserved, so we can
hide the "key" in the low 12 bits of hwc->config.

We extract the key from hwc->config and then quickly find the
template.

Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Reviewed-by: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1268908387.13901.127.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-18 17:03:51 +01:00
Lin Ming
8ea7f54410 x86, perf: Fix comments in Pentium-4 PMU definitions
Reported-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1268705556.3379.8.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-16 09:37:46 +01:00
Cyrill Gorcunov
e449526282 perf, x86: Enable not tagged retired instruction counting on P4s
This should turn on instruction counting on P4s, which was missing in
the first version of the new PMU driver.

It's inaccurate for now, we still need dependant event to tag mops
before we can count them precisely. The result is that the number of
instruction may be lifted up.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <1268629102.3355.11.camel@minggr.sh.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-15 08:14:34 +01:00
Cyrill Gorcunov
a072738e04 perf, x86: Implement initial P4 PMU driver
The netburst PMU is way different from the "architectural
perfomance monitoring" specification that current CPUs use.
P4 uses a tuple of ESCR+CCCR+COUNTER MSR registers to handle
perfomance monitoring events.

A few implementational details:

1) We need a separate x86_pmu::hw_config helper in struct
   x86_pmu since register bit-fields are quite different from P6,
   Core and later cpu series.

2) For the same reason is a x86_pmu::schedule_events helper
   introduced.

3) hw_perf_event::config consists of packed ESCR+CCCR values.
   It's allowed since in reality both registers only use a half
   of their size. Of course before making a real write into a
   particular MSR we need to unpack the value and extend it to
   a proper size.

4) The tuple of packed ESCR+CCCR in hw_perf_event::config
   doesn't describe the memory address of ESCR MSR register
   so that we need to keep a mapping between these tuples
   used and available ESCR (various P4 events may use same
   ESCRs but not simultaneously), for this sake every active
   event has a per-cpu map of hw_perf_event::idx <--> ESCR
   addresses.

5) Since hw_perf_event::idx is an offset to counter/control register
   we need to lift X86_PMC_MAX_GENERIC up, otherwise kernel
   strips it down to 8 registers and event armed may never be turned
   off (ie the bit in active_mask is set but the loop never reaches
   this index to check), thanks to Peter Zijlstra

Restrictions:

 - No cascaded counters support (do we ever need them?)
 - No dependent events support (so PERF_COUNT_HW_INSTRUCTIONS
   doesn't work for now)
 - There are events with same counters which can't work simultaneously
   (need to use intersected ones due to broken counter 1)
 - No PERF_COUNT_HW_CACHE_ events yet

Todo:

 - Implement dependent events
 - Need proper hashing for event opcodes (no linear search, good for
   debugging stage but not in real loads)
 - Some events counted during a clock cycle -- need to set threshold
   for them and count every clock cycle just to get summary statistics
   (ie to behave the same way as other PMUs do)
 - Need to swicth to use event_constraints
 - To support RAW events we need to encode a global list of P4 events
   into p4_templates
 - Cache events need to be added

Event support status matrix:

 Event			status
 -----------------------------
 cycles			works
 cache-references	works
 cache-misses		works
 branch-misses		works
 bus-cycles		partially (does not work on 64bit cpu with HT enabled)
 instruction		doesnt work (needs dependent event [mop tagging])
 branches		doesnt work

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100311165439.GB5129@lenovo>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11 18:51:08 +01:00